Membrane nanotubes (NTs) are dynamic communication channels connecting spatially separated
cells even over long distances and promoting the transport of different cellular cargos.
NTs are also involved in the intercellular spread of different pathogens and the deterioration
of some neurological disorders. Transport processes via NTs may be controlled by cytoskeletal
elements. NTs are frequently observed membrane projections in numerous mammalian cell
lines, including various immune cells, but their functional significance in the ‘antibody
factory’ B cells is poorly elucidated. Here, we report that as active channels, NTs
of B-lymphoma cells can mediate bidirectional mitochondrial transport, promoted by
the cooperation of two different cytoskeletal motor proteins, kinesin along microtubules
and myosin VI along actin, and bidirectional transport processes are also supported
by the heterogeneous arrangement of the main cytoskeletal filament systems of the
NTs. We revealed that despite NTs and axons being different cell extensions, the mitochondrial
transport they mediate may exhibit significant similarities. Furthermore, we found
that microtubules may improve the stability and lifespan of B-lymphoma-cell NTs, while
F-actin strengthens NTs by providing a structural framework for them. Our results
may contribute to a better understanding of the regulation of the major cells of humoral
immune response to infections.
